Latest filename from directory or list of files - whitespace safe

gistfile1.txt

#!/usr/bin/env python3

import sys
import os

# prints name of newest file - ignores directories

# 3 cases
# list of files
# a single argument that is a directory
# no arguments - the current directory

def append_slash_if_missing(dir_path):
    """Appends a slash to the directory path if it's missing."""

    if dir_path and dir_path[-1] != os.path.sep:
        dir_path += os.path.sep
    return dir_path

def main():
    if len(sys.argv) > 2:
        # a lit of files
        listToProcess = sys.argv[1:]
    elif len(sys.argv) == 2:
        if os.path.isdir(sys.argv[1]):
            dir = append_slash_if_missing(sys.argv[1])
            listToProcess = [ dir + item for item in os.listdir(dir) ]
        else:
            listToProcess = sys.argv[1:]
    else:
        listToProcess = os.listdir(".")

    newest_file = None
    newest_time = 0
    for filename in listToProcess:
        #print(f"FILENAME {filename}")
        if os.path.isfile(filename):
            file_time = os.path.getmtime(filename)
            if file_time > newest_time:
                newest_time = file_time
                newest_file = filename
    if newest_file:
        print(f"{newest_file}")
        


if __name__ == "__main__":
    sys.exit(main())